1. Field of the Invention
The present invention relates to a method of producing operation signals used to operate an object such as a robot or a character appearing in video games, which has a body analogous to the body of a human being or an animal and performs body actions for viewing by people, (hereinafter referred to as a “motion object”), so that the object automatically behaves with natural and living creature-like actions in a manner giving emotional expressions as well. Also, the present invention relates to an apparatus for producing operation signals for the motion object, and a program product for producing the operation signals.
2. Description of the Related Art
A series of body actions of a motion object (robot) are controlled by outputting operation signal commands to actuators of the motion object. Hitherto, body operation signals for conventional robots and video game characters have been mostly produced using any of the following methods.
(1) Method of Copying Motions of a Real Human Being or Animal
This method is represented by a motion capture system. Specifically, a motion object is operated so as to follow captured motions of a real human being or animal, thereby giving natural feeling and emotional expressions to the motions of the object.
(2) Method of Manually Creating Action Data
In many cases, action data of a motion object is created beforehand by game designers and other persons.
(3) Method of not Intending Impression Production and Artistic Effects of Motions with Direct Purpose
As an alternative method, motions are designed to achieve another purpose instead of an explicit purpose for causing a motion object to behave like a living body with emotional expressions. There is also a method of creating motions in an automatic manner. For example, motions of forelegs and hind legs of a four-footed robot are automatically enlarged to increase amounts of advance. Those artificial motions for practical purpose are eventually very similar to motions of actual animals in some cases when visually perceived.
With the above conventional method (1), however, since the motion capture is based on identical copying, a difficulty arises in correction and interruption of motions. In particular, it is difficult to make interactive correction (which is required, for example, in environment including complicated configurations of the ground surface or the presence of an obstacle to correct motions so that the object is avoided from striking against the ground or the obstacle).
Also, in general, size of data recording real-life motions are large. Because those data must be collected and stored beforehand, a repertory of motions capable of being held by a system is also restricted. Further, for operating a motion object in imitation of an imaginary animal, collected data must be modified for adaptation to individual cases if the structure and size of the motion object differ from those of the imaginary animal.
In the above conventional method (2), since action data created by designers is also large in size, there occurs a problem similar to that with the above conventional method (1). The above conventional method (2) also has a disadvantage in that since the action data is subjectively created by the designer, properness of expressed actions is not theoretically ensured, and a burden for producing actions is imposed on the designer.
In the above conventional method (3), a manner of controlling psychological and emotional impressions expressed by actions is not yet realized.
In the field of psychology and dance study, there is known the Laban-Bartenieff-Kestenberg theory for correlating the degree and evolution and growth of the psychological states with features of body actions. The theories of Laban Movement Analysis, Bartenieff Fundamental Theory and Kestenberg Movement Analysis (see references: The Mastery of Movement, Rudolf Laban, Macdonald & Evans, 1960, Body Movement Coping with the Environment, Irmgard Bartenieff et al., Gordon and Breach Publishers, 1980, The Meaning of Movement, Janet Kestenberg Amighi et al., Gordon and Breach Publishers, 1999, and Making connections—Total Body Integration through Bartenieff Fundamentals Peggy Hackney, Gordon and Breach Publishers 1998) have been primarily used to estimate human psychological state from human movements. By utilizing that theory not for emotion estimation but for emotion expression, the inventors have previously proposed a basic idea for automatically producing movements of a motion body, which allow people to feel emotional and psychological expressions from body actions of the motion body (Japanese Patent Application Publication No. 2001-34305 entitled “Controller of Operation Body”).